This invention involves unsaturated carboxylic acid ester-amides which contain halogen atoms in their structures. In general, it concerns polycarboxylic acid ester-amides of polyhalogenated alcohols. In particular, it deals with .alpha.,.beta.-unsaturated polycarboxylic acid ester-amides of halogenated alcohols of the formula ##STR2## wherein R is a divalent hydrocarbon containing at least 1 and no more than 10 carbon atoms,
X is bromine or chlorine, and PA1 R' is H, X or a monovalent hydrocarbon containing at least 1 and no more than 20 carbon atoms.
Typical ester-amides of this invention are the maleates, the fumarates, the itaconates, the aconitates, etc. These typical ester-amides are derivatives of .alpha.,.beta.-unsaturated polycarboxylic acids, all of which contain the essential structure ##STR3## By designating the halogenated alcohols (A) shown above as ZOH, the new ester-amides of this invention can be represented as containing the essential structure (C): ##STR4## A few typical polycarboxylic acids from which the essential structure (C) can be derived are HOOC--CH=CH--COOH, ##STR5##
The .alpha.,.beta.-polyunsaturated carboxylic acid may also be defined as having the structure, ##STR6## wherein A and A' are each selected from the class consisting of --H, --X, --CN, --COOZ, --(CR'.sub.2).sub.n COOZ, and R', where at least one A or A' has a --COOZ group therein, preferably at least one A or A' representing H or X; n has a numerical value of 1 to 10; and Z is a radical selected from the class of H and ##STR7##
The ester-amides of this invention are readily prepared by esterifying the acids ##STR8## with the alcohol R'CX=CXR--OH by procedures well known in the art. Instead of the carboxylic acid, the corresponding acid chloride or anhydride may be used. When the acid chloride is used, preferably, a hydrohalide acceptor such as a tertiary amine, as for example, the trialkyl amines, dimethylaniline, pyridine, etc., are used in the reaction: ##STR9## The ester exchange reaction, using the lower alkyl esters of the above acid, for example and the alcohol may be used to prepare the new esters of this invention, thus: ##STR10##
The amide group in the ester-amides of this invention are introduced by ordinary amidification reactions either before or after the introduction of the halogenated ester group shown above. This may be done with either a free acid group of the polycarboxylic acid or its half ester, or with the acid group converted to the acid halide, by reaction with ammonia or the appropriate amine to give the desired amide group.
The amide groups may be represented by the formula --CON(R").sub.2 wherein R" includes the groups included in R' as defined above but preferably is an alkyl, alkenyl aryl or cycloalkyl group of 1-10 carbon atoms. The R" may also have an hydroxy or amino group attached such as in ethanol and diethanolamines, p-aminophenylamine, etc.
Typical divalent hydrocarbon radicals represented by R include: ##STR11##
The new ester-amides of this invention are useful with their halogen content as flame retardants and for the preparation of flame-retardant compositions. Those ester-amides which contain an activated terminal vinyl or vinylidene group, ##STR12## such as the itaconates, are particularly useful for the preparation of homopolymers and copolymers with other vinyl monomers, including other esters of this invention. Other ester-amides of .alpha.,.beta.-unsaturated dicarboxylic esters, such as the maleates and fumarates, are particularly useful for the synthesis of copolymers. The esters of this invention find utility not only as monomers but also as plasticizers and fire-retardant additives to other non-polymeric as well as polymeric materials. Especially are they suited, as vinyl monomers, alone or with other monomers, for co-reaction with other unsaturated polyesters, typical examples of which are the polyalkylene maleates and fumarates, as well as those unsaturated polyesters modified by non-olefinic polycarboxylic acids such as phthalic, tetrachlorophthalic, tetrabromophthalic or chlorendic anhydride.
The polymerizable monomers of this invention, as illustrated, for example, by the itaconates, etc., are readily polymerized or copolymerized to soluble polymers by radical generating initiators, such as the peroxides, hydroperoxides, peracetates or by redox systems including hydrogen peroxide with ferrous salts or sodium bisulfite, potassium or sodium persulfate with bisulfate, etc.; ultraviolet light, ionizing radiation, etc. Radical polymerizations are well known in polymer science and are applicable to the monomers of this invention.
The production of soluble polymers, especially from the new ester-amides containing more than one double bond, particularly those having the structure ##STR13## for example, NH.sub.2 C(O)CH.sub.2 =CHCOOCH.sub.2 CX=CHX, is surprising and unexpected since the corresponding allyl esters, CH.sub.2 =CHCOOCH.sub.2 CH=CH.sub.2, and the acetylenic esters, CH.sub.2 =CHCOOCH.sub.2 C .tbd.CH, cross-link under radical polymerization as shown in J. Polymer Science, Vol. 5, pp. 323-337, 813-832, 999-1014 (1967). These monomers also differ from the corresponding allyl and acetylenic esters in that they do not polymerize with anionic initiators, since the halogen atoms in the new esters of this invention destroy the anionic initiator used. Further, these new ester-amides cannot be prepared directly from the acetylenic ester by halogenation, since the halogenation is not selective and causes halogenation, to a great degree, of the vinyl bond in the acid, thus ##STR14## thereby destroying the polymerizability of the original ##STR15##
Some of the polymers obtained by the radical initiation of certain ester-amides of this invention, such as ##STR16## yield polymers having, at least in part, repeating units of the formula ##STR17## which repeating units are similar to those obtained by the post-halogenation of the completely linear polymers obtained by the anionic polymerization of the acetylenic esters of the acrylic acids, as shown in J. Polymer Sci., Vol. 5, pp. 813-832, 999-1014 (1967). However, the related polymers of this invention, prepared by radical polymerization are not entirely linear polymers, but, as a result of the well-known radical-transfer phenomenon, particularly in systems comprising halogenated compounds, are branched polymers. This is particularly advantageous when the polymer is intended for use as a fire-retardant additive, since the solution and melt viscosities of branched polymers are notably lower than the related linear polymers of the same molecular weight. This lower viscosity increases the compatibility of the polymers with other polymers, and allows the use of lower temperatures in processing the polymers or mixtures of polymers. Many of the polymers prepared from the monomers of this invention, however, have no relation to the post-halogenated acetylenic ester polymers mentioned hereinabove. For example, the itaconic ester-amide polymers, and the copolymers of the maleic or fumaric ester-amides are readily prepared by the radical initiation of the monomers of this invention, whereas the ester-amides of itaconic acid, fumaric acid and maleic acid, etc., cannot be polymerized anionically, and thus are unavailable for post-halogenation.
Another major advantage accrues from the use of many of the monomers of this invention, particularly with the ester-amides of the .alpha.,.beta.-unsaturated polycarboxylic acid such as the itaconates, maleates, fumarates, citraconates, etc. The only requirement of the ester-amides of this invention is that at least one of the carboxyl groups of said polycarboxylic acid is esterfied by the alcohol, R'--CX=CXR--OH; the remaining one or more carboxyl groups may be converted to one or more amide groups, saturated or unsaturated, such as amides of ammonia, primary amines and secondary amines, such as methylamine, diethylamine, diethanolamine, cyclohexylamine, allylamine, diallylamine, aniline, N-methyl aniline, p-aminophenol, m-aminobenzoic acid, anthranilic acid, etc.
Where there is a third carboxylic acid group, such as in aconitic acid this third carboxylic acid group may be converted to an unsaturated ester or amide such as the vinyl, allyl, methallyl, crotyl ester, etc., in which case the new derivative can be polymerized to insoluble, infusible polymers. This third carboxylic acid group thus may be reacted with a saturated, unsaturated, carbocyclic or heterocyclic alcohol or amine, as for example, methyl, ethyl, propyl, amyl, hexyl, stearyl, benzyl, allyl, propargyl, butynyl, .beta.-N,N-dimethylaminoethyl, cyclohexyl alcohols and amines, etc., such as .beta.-hydroxyethyl alcohol or amine, .beta.-hydroxypropyl alcohol or amine, .beta.-hydroxyethyl alcohol or amine, dimethylamine, diethylamine, dipropyl amine, dibenzyl amine, diphenylamine, dicyclohexyl amine, etc.
A few examples of such typical monomers which polymerize to insoluble, infusible polymers are ##STR18##
The monomers of this invention containing a ##STR19## wherein P represents hydrogen, methyl, chlorine, bromine, cyano and phenyl, homopolymerize readily with radical initiation such as by means of a peroxy compound, ultraviolet light or ionizing radiation, whereas those monomers having substitution on the alpha and beta carbon atoms homopolymerize under radical initiation less readily and in some cases not at all, but copolymerize more readily according to their reactivity and selective constants, r.sub.1 and r.sub.2.
With unsymmetrical dibasic and tribasic acids, such as itaconic and aconitic acids, the exact positioning of the amide group with respect to the two or more carboxylic acid groups, and likewise the positioning of the ester group is difficult to determine and very likely the products are a mixture of the various possible positional isomers. Therefore, while a particular formula may be used to represent the product, such as for an ester-amide of itaconic acid, ##STR20## it is understood that a substantial part of the compound and even a major portion may actually have the isomeric formula ##STR21##
The homopolymerizations and copolymerizations of the monomers of this invention may be performed (1) in mass, that is, neat, in the absence of added solvents or dispersion media; (2) in suitable organic substances which are solvents for the monomers as well as the polymers, or which are solvents for the monomers and not for the polymers, in which cases the polymers precipitate from the media; or (3) in emulsion systems which are well known in the art and which comprise an emulsifying agent such as soaps, synthetic emulsifiers, such as dodecylbenzene sulfonate sodium salts, sodium sulfodioctylsuccinate and the like, in water. In the emulsion systems water soluble radical initiators such as potassium persulfate, hydrogen peroxide, sodium perborate, urea peroxide, etc., are used alone or in the presence of a redox agent, such as sulfur dioxide, sodium bisulfite, ferrous sulfate, etc.
Thus, the polymers and copolymers of this invention can be prepared by the vinyl type polymerization by means of radical initiators such as the peroxy and azo catalysts as such or as redox systems as well as by ultraviolet and ionizing radiation. Of the azo-type catalysts, azobisisobutyronitrile is a typical example and is usually preferred. The peroxy catalysts are illustrated by stearoyl, lauroyl and butyroyl peroxide, but for economic reasons benzoyl peroxide, tertiarybutyl peroxide and tertiary-butyl peracetate are preferred, but, any of the other well known peroxy catalysts such as cumene peroxide and the like can also be used.
In the polymers and copolymers derived from the monomers of this invention, the repeating unit structure derived from these monomers are represented as follows: ##STR22##
Alternately, the polymerization may be achieved thermally, simply by heating to generate the initiating radicals. The polymerization can be performed over a wide range of temperatures depending upon whether the system used is a mass, a solution or an emulsion polymerization and whether the initiation is by a redox system, ultraviolet or ionizing radiation. With ionizing radiation, polymerization can be achieved at temperatures as low as -40.degree. C., but usually at ambient temperatures. The redox polymerizations can be performed at 0.degree. to 70.degree. C., and the thermal polymerizations can be performed up to temperatures of the order of 75.degree. to 125.degree. C. or higher.
The new monomers of this invention can be copolymerized with other vinyl monomers such as acrylic and methacrylic esters such as the methyl, ethyl, propyl, butyl, hexyl, cyclohexyl, dodecyl, etc. esters. In addition to, or in lieu of these acrylic type esters used in such copolymerizations, any other copolymerizable monovinyl or monovinylidene comonomer or mixtures thereof can be used, for example, vinyl esters, that is vinyl acetate, and the monovinyl esters of saturated and unsaturated, aliphatic, monobasic and polybasic acids: propionic, isobutyric, valeric, caprylic, caproic, oleic, stearic, acrylic, methacrylic, crotonic, oxalic, malonic, succinic, glutaric, adipic, suberic, azelaic, maleic, fumaric, itaconic, mesaconic, hexahydrobenzoic, citric, trimesic, etc., as well as the corresponding allyl, methallyl, etc. esters of the aforementioned acids, acrylonitrile, methacrylonitrile, methacrylic acid, hydroxy propyl methacrylate, etc.; amides such as acrylic amide; itaconic acid monoesters and diesters, such as the methyl, ethyl, butyl, allyl esters, the maleic and fumaric acid monoesters, diesters and their amide and nitrile compounds, such as diethyl maleate, maleyl diamide, itaconamide, fumaryl dinitrils, dimethyl fumarate, etc.; ethers, such as methallyl ethyl ether, vinyl ethyl ether, vinyl butyl ether, allyl propyl ether, vinyl cyclohexyl ether; cyanuric acid derivatives having one copolymerizable unsaturated group attached directly or indirectly to the triazine ring, such as allyl diethyl cyanurate, vinyl diethyl cyanurate; the dienes such as butadiene, isoprene, etc.; as well as the partial, soluble or fusible polymerizable polymers of the hereinabove listed monomers, etc.
Typical suitable aromatic comonomers include vinyl aryl compounds such as styrene, vinyl naphthalene, vinyl toluene, vinyl xylene, vinyl phenol, vinyl ethyl benzene, vinyl dimethyl naphthalene, vinyl diphenyl, etc.; chloro-styrenes, etc., vinyl phenyl ether, vinyl benzoate, vinyl naphthoate, vinyl methyl phthalate, allyl ethyl phthalate, allyl propyl phthalate, etc.
The polymeric compositions of this invention are particularly useful as coating compositions on all types of substrates, including cellulose in its various forms, such as paper, wood, paper board, wood board, wood pulp, regenerated cellulose in film or fiber form, laminates of various types including those prepared from fibrous fillers bonded with urea, melamine, epoxy and polyester resins, plaster board, concrete in its various forms such as slabs, blocks and the like. They may also be used as impregnants for porous bodies such as the compositions hereinabove named, as well as for synthetic and natural sponges, etc.
Particularly do they find use as bonding agents and adhesives for solid, porous and foamed bodies. They can be used alone or admixed with each other or with other copolymerizable monomers, unsaturated or saturated polymers, in the absence or presence of dyes, pigments, plasticizers. For coating, impregnating or adhesive compositions where the presence of small amounts of solvent in the cured composition is not objectionable they can be mixed with volatile or non-volatile solvents best suited to the particular application.
The polymers of this invention are also useful in the preparation of copolymers with unsaturated alkyd resins. In carrying this portion of the invention into effect, an esterification product of a polyhydric alcohol and an alpha, alpha-unsaturated polycarboxylic acid is first prepared in accordance with techniques now well known to those skilled in the alkyd resin art, such as ethylene glycol maleate, propylene glycol maleate, ethylene glycol maleate-phthalate, ethylene glycol maleate-acrylate, propylene glycol-fumaratemethacrylate and the like.
In many cases, instead of copolymerizing a single monomer of this invention with a single alkyd resin, mixtures can be used of two or more such monomers with a single alkyd resin, or a single monomer can be used with two or more alkyd resins, or a mixture of two or more monomers with two or more alkyd resins.
The polymers of this invention can be used alone or with fillers, dyes, pigments, opacifiers, lubricants, plasticizers, natural and synthetic resins or other modifying bodies in, for example, casting, molding, laminating, coating applications, and as adhesives, impregnants, and protective coatings.
In preparing copolymers, the monomers of this invention can constitute as much as 98 to 99.5% by weight of the whole, or the modifying comonomer or alkyd resin can constitute 98 to 99.5% of the whole.
In general, the proportions of the components used in a particular formulation will depend upon the particular properties desired in the interpolymer. For most applications, it is preferred to use 20 to 80 percent of the monomers of this invention and from 80 to 20 percent of the modifying polymer or monomer, since within these ranges interpolymers best adapted for most commercial applications can be produced.
Within these ranges the new interpolymers have a wide range of properties. For example, depending upon the particular crosslinking polymer and any modifying polymer or monomer, the particular proportions thereof, the conditions of polymerization, such as the temperature, pressure, presence or absence of additives, etc., and the extent of polymerization, they can vary from soft flexible bodies to hard rigid masses of varying resistance to solvents.
For coating or impregnating applications where the presence of a small amount of solvent in the cured composition is not objectionable, the mixed starting component can be diluted with volatile or non-volatile solvents or diluents best suited for the particular service application, and then can be polymerized after the application of the solution to the particular article to be coated or impregnated, or impregnated and coated. By suitable selection of the starting material and the conditions of interpolymerization, interpolymers can be obtained in an insoluble, infusible state practically resistant to the destructive effect of other chemical bodies, such as acid, bases, salts, solvents, swelling agents, and the like.
When it is desired to modify the properties of the crosslinkable monomers of this invention, this can be accomplished by copolymerizing a mixture comprising at least one such polymer with at least one copolymerizable monomer containing at least one unsaturated ethylenic, or acetylenic hydrocarbon radical, more particularly, a CH.sub.2 =C&lt; radical, such as vinyl, allyl, methallyl, vinylidene, etc., or with a copolymerizable compound containing a --CH=CH--, or a --CH=C&lt;,
or a &gt;C=C&lt; grouping, for example as in vinylidene fluoride, vinylidene cyanide, vinyl propionate, maleic anhydride, or its esters and amides, methyl maleic anhydride, tetrafluoroethylene, etc.
In preparing copolymers of the crosslinkable monomers with polymerizable comonomers such as methyl methacrylate, styrene, acrylonitrile, and the like, the crosslinkable polymer can constitute as little as 0.1 percent by weight of the whole, whereas in other cases the crosslinkable polymers can constitute as much as 98 to 99 percent of the whole. The proportion of the components in a particular formulation will depend upon the particular comonomers used and the particular properties desired in the copolymer. The polymers and copolymers can be prepared most readily by ionizing radiation.
Certain monomers of this invention, particularly those having the structure ##STR23## are particularly suited for grafting to polymers in fiber form, by techniques well known in the art to render the fibers non-burning, such as to fibers or textiles of the nylon, polyvinyl alcohol, regenerated cellulose, cotton, etc. They are particularly useful in this respect for cellulose fibers and fabric such as derived from rayon or cotton. One particularly useful method is to form a redox metal complex of the acidic cellulose, or, of the reaction product of cellulose with carbon bisulfide, and to graft the monomer directly to the cellulose.
Various methods of practicing the invention are illustrated by the following examples. These examples are intended merely to illustrate the invention and not in any sense to limit the manner in which the invention can be practiced. The parts and percentages recited therein and all through this specification, unless specifically provided otherwise, refer to parts by weight and percentages by weight.